Television system



-0t.25,193z. 'l C. L. DMS 1,884,593

TELEVISION SYSTEM Filed Jul'y 23, 1930 2 Sheets-Sheet l 'La 1% INVENTOR- (Da/wks) oCt. 25, C. L DAVIS TELEVISION SYSTEM 2 Sheets-Sheet 2 Filed July 23. 1930 INVENTOR. S3, @m/

ATTORNEY'.

Patented Oct. 25, 1932 UNITED STATES PATENT OFFICE CHESTER I... Davis, or

KEOKUK, IOWA, ASSIGNOR TO WIRED RADIO, INC., F NEW YORK,

N. Y., A CORPORATION OF DELAWARE TELEVISION SYSTEM Application' led July 2S,

discharge takes place across a variable capac-l ity gap in accordance with the variation in the position of a potential node in atelevision receiving circuit.

Another object of my invention is to provide a construction of television screen for connection 1n a television receiving c1rcu1t wherein the screen comprises an inductance element and a plate member variably and spacially related with respect thereto for the luminous discharge of high frequency electrical energy between the inductive screen and the plate member which Vis associated therewith.

Still another object of my invention is to provide a constructionof image reproducing screen for television systems wherein a concave plate member is disposed adjacent an inductance member and serves as an adjustable capacity unit and reiiector for rays of light occurring from luminous discharge between said inductive screen and said plate member.

Other and further objects of my invention reside in an arrangement of luminous discharge screen for television receiving systems as set forth more fully in thespecication hereinafter following byreferenceto the accompanying drawings, in which:

Figure 1 diagrammatically illustrates a television receiving circuit to the output of which the image reproducing screen of my invention is electrically connected; Fig. 2 is a cross-sectional view through the image reproducing screen of my invention mounted c in a socket engaging base takenl on line 2-2 of Fig. 3; Fig. 3 is a vertical longitudinal sectional view of the image reproducing screen taken on line 3--8 of Fig.'2; Fig. 4 is a lateral cross-sectional view on line 4-4 of Fig. 2; and Figs. 5a, 5b, 5c and 5d illustrate a series of characteristic curves of the image reproducing screen embodying the principles of my invention.

1930. Serial No. 470,157.

The image reproducing screen of my invention is employed in television systems of the character described in my Letters Patent No. 1,7 56,086, dated April 29, 1930, entitled Signaling system, and Letters Patent 1,7 89,219, dated January 13, 1931, entitled Glow discharge device and application Serial No. 414,957, iiled December 18, 1929, entitled Television system. For a further understanding of the television system of my invention reference is made to my copending application Serial No. 460,760, filed J une 12, 1930, entitled Television system.

Referring to the drawings in detail, ref erence character 1 designates an antenna system connected to primary winding 2 of a coupling transformer having 'a secondary winding 3 tuned by variable condenser 7 and connected to the radio frequency amplilier designated at 4. A detector is indicated at 5 coupled through tuned circuit 8 with the'output of radio frequency amplifier 4. An oscillator 6 is coupled to detector 5 and has the television image reproducing screen 12 connected Vthereto as shown. The screen comprises a pair of electrodes designated at 11 and 14 disposed within a vessel 21.. One of the electrodes shown at 11 consists of a concave plate member which is capacitively related to the inductance element 14. The electrode 1l is concave in shape and serves as a' reflector for the luminous discharge which takes place between the turns of the electrode 14 and the surface ofthe plate 11. The turns of inductance 11 are supported by insulated transparent rods 14a and 146 carried by laterally extending member 140 mounted in the glass ress 21a of tube 21. The spacial relation o? is varied by movement of screw members 17 suitably supported within the vessel 21 on member 16 and terminating in rotatable jaw guides 17 b on the rear of the concave plate the plate 1l with the conductor 14 member 11. Member 16 is supported in the able exteriorly of the vessel 21 to accurately position the plate member 11 with respect to the inductive screen 14 vby following the resonant to the exciting source.

magnetic member 17a by means of a bar magnet indicated at 23 which is moved in a spiral path outside the vessel 21 whereby the plate 11 may be advanced or retracted to a selected osition with respect to the turns of inuctance 14. The terminals of the screen are brought out through suitably spaced insulated tubes to contacts' 24 and 25 in the base 26 b which the image reproducingV screen ma mounted in a suitablesocket.

e series of curves shown at Fig. 5a, Fig. 5b, Fig, 5c and Fig. 5d show the different characteristics of the glow discharge tube of my invention. The electrodes of the glow discharge tube connect in circuit with the high frequency oscillator and are subject to a continuous luminous discharge by oscillations which are sustained in the circuit 10- 11-14-15 of the oscillator shown in Fig. 1. The driving motor 9 periodically varies the tuning of condensers 74-8-10 at a rate proportional to changes in frequency of the transmitted signa ing energy. As illustrated in Fig:J 5a the normal signaling po tential varies along the inductance screen 14 according to the curve C. Fig. 5b represents the required ionization potential for the variabl spaced reector and inductance. In

' or er to secure uniform illumination of the screen,`the characteristic shown in 5b should be maintained according to curve B. In Fig. 4c the effect of uniformly spacing the electrodes is shown where the potential distribution is non-uniform and which will produce non-uniform illumination along the conductor irrespective of the modulated energy. Obviously this is an undesired condition and is remedied by they arrangement l which I em loy.

Due to t e fact that the potential of the antinodes of the circulating current along the turns of the inductance 14 rapidly decreases as the circuit of the glow dischar e tube recedes from resonance condition with respect to the exciting source, higher potential is required to cause-discharge of light luminous intensity at the points where such potential decreases. This provides uniform response irrespective of forced conditions. In Fig. 5d I have shown the distribution of voltage and current along the electrode 14. The resonant point is indicated by the maximum voltage condition-at point K, that is where the clrcuit has a frequency characteristic The adjustments of the circuit are such that uniform intensity of glow discharge is obtained even though the circuit is not being modulated. Under conditionsof modulation the node extends from one osition to another along the turns of the in uctance '14 and all of these moving potential nodes are integrated in i forming an image of the distant object.

' The structure of the television screen will "i be-clearly'unders'tood from Figs. 2, 3 and 4 wherein the envelope 21 encloses the inductive electrode 14 and the concave mirror electrode fthe screen from the out ut circuit by removing the tube from a suita le supporting socket and replacin the same by a renewal tube. For certain c asses of television work it may be desirable to use tubes of different color characteristics so that the removal of the tube and replacement of a substitute tube may be made readily. The envelope of the tube may be filled with such gases as neon, krypton, nitrogen, etc., having different color characteristics for producing different characteristics of glow as maybe desired. The structure of the image reproducing screen is such as to insure sharpness in vision of the reproduced image. j

While I have described my invention in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

v 1. A television glow discharge screen comprisingl an inductance member having the turns t ereof disposed parallel one to another and a reflective Plate of conductive material variably adjustable adjacent said inductance member, said plate having a concave surface immediately` adjacent said inductancey mem- 2. A television glow discharge tube comprising an inductive member and a reflective plate member adjustably positioned with respect thereto and means for shifting said p ate member to selected ca acitative positions with res ct to'said in uctive member.

3. A television screen comprising an inductive member anda plate member, said inductive' meniber including a multiplicity of parallel extending-turns extending laterally with respect to said plate member, an envelope enclosingsaid members and fneans for shifting said plate member with respect to said inductive member.

4. A television screen member comprising an inductive member and a concave plate, members positioned adjacent thereto, an cn- .velope enclosin said members in an lionizing 4atmosphere an means for adjusting said concave plate to dilering capacitative positions with respect to said inductive member.

ijf),

5. A television image reproducing screen.

electrodes comprising an inductive member having a multiplicity of parallel disposed turns located in the same plane, and the other of said electrodes comprising a concave plate member adj ustably mounted adjacent said inductive member with the turns of said inductive member disposed at dierent distances from said concave plate member.

6. A television image reproducing screen comprising a tube having a base, contacts extending rom said base, a press within said tube and means .extending from said press comprising a conductive member bent upon itself with parts of the member extending in the same plane and an adjacent member substantially in the form of a concave conductive ymirror adj ustably positioned behind said concave member, and connections between said conductive member and' said conductlve mirror wlth sa1d contacts.

7. A television image reproducing screen comprising a tubular envelope, a supporting base carrying said envelope, a press connected with said base, an -inductance element supported by said press with the turns thereof disposed in the same vertical plane, and a conductive mirror supported by said press in a' position adjacent said inductance element, and means for adjusting the spacial relation between said conductive`mirror and said inductance element.

8. A televisionimage reproducing screen comprising an evacuated envelope, a base secured to said enevelope, a press connected with said base, a pair of electrodes supported by said press, one of said electrodes comprisf ing a conductive member bent in the form of an inductance with the turns thereof disposed in the same vertical plane and the other of said electrodes com rising concave conductive mirror dispose adjacent saidV first mentioned electrodes, and means for adjustably positioning said concave conductive mirror indifferent glow discharge vpositions with respect to turns of said inductance.

Iniestimony whereof I aiix my signature.

CHESTER L. DAVIS. 

